WARSAW (Reuters) - Pilots of the doomed aircraft carrying Poland's President Lech Kaczynski received at least a dozen warnings from on-board systems to regain altitude during the last minute before the crash, according to transcripts from its cockpit recorders released on Tuesday.

Prime Minister Donald Tusk's government decided to publish the transcripts to quell media speculation about the reasons for the April 10 crash, which also killed Poland's top military commanders, its central bank governor and many lawmakers.

"Pull up, pull up... Terrain ahead," the on-board warning system told the pilots numerous times just before the crash.

It was not clear from the transcripts why the pilots only tried to pull higher when it was already too late.

Polish media have speculated that Kaczynski himself may have contributed to the crash by encouraging pilots to disregard Russian traffic controllers' advice and to land the plane despite the poor weather conditions.

The transcript provided no evidence of this, though three minutes before the crash it quoted an unidentified person in the cockpit as saying: "(S)he will be annoyed if..."

It did not make clear who the subject of the sentence was and said the rest of the sentence was unintelligible.

One of the pilots cursed after the plane hit a tree -- a collision that flipped the Tupolev Tu-154 military plane upside down. The last sound recorded was a prolonged expletive uttered by an unidentified person in the cockpit.

IN A HURRY

Kaczynski and his entourage had been running late for a planned ceremony in nearby Katyn forest marking the 70th anniversary of the murder of some 22,000 Polish army officers and intellectuals there by the Soviet NKVD secret police.

Some 15 minutes before the crash, the pilots told the head of Poland's diplomatic protocol, Mariusz Kazana, who was in the cockpit, that the plane would not be able to land because of the thick fog, the transcripts showed.

"Well then we have a problem," Kazana replied. A few minutes later, he returned to the cockpit to say the president had not yet made a decision about what they should do next.

A Polish prosecutor who took part in a probe into the crash undertaken by Russia has said he believes poor training, lack of money for test flights and incorrect flight procedures in the Polish air force all contributed to the disaster.

Russia handed over copies of the cockpit recordings to Polish Interior Minister Jerzy Miller on Monday. The original recordings will stay in Russia until its probe is completed.

Miller and Russian Deputy Prime Minister Sergei Ivanov praised cooperation between their countries over the crash as transparent and unprecedented.

Both Warsaw and Moscow have said the tragedy, which triggered a big outpouring of solidarity in Russia, can help them improve ties long strained by disputes over issues ranging from gas supplies to missile defence and NATO enlargement.

Kaczynski's twin brother Jaroslaw criticised Tuesday's decision to publish the transcripts before the families of the victims had had time to read them.

Kaczynski, leader of the right-wing main opposition party, Law and Justice, is hoping to replace his brother in a presidential election set for June 20, though opinion polls suggest he will lose to Acting President Bronislaw Komorowski.

Komorowski is the candidate of Tusk's governing centrist Civic Platform. He became acting president after the crash in his capacity as speaker of Poland's lower house of parliament.

If neither man wins more than half of the votes on June 20, a second, decisive round will be held on July 4.

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